New iPhone 11, power button intermittent

Sometimes the screen won't turn off with the power (right) button - no 'click' sound or anything. I did a reset, keeping the data and apps and it didn't help. When the screen isn't turning off, it will still set off the emergency buzzer thing if I hold the button long enough.

I can't seem to repeat it predictably. I just picked it up now from sleep and it wouldn't turn off from the lock screen. Then it started working again after I took a screenshot. But then other times it will become unresponsive after I've been using the phone a lot.

Also my battery seems to be draining much faster compared to what my kids phones are (same iphones).